1 /*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "verification.h"
18
19 #include <iomanip>
20 #include <sstream>
21
22 #include "art_field-inl.h"
23 #include "mirror/class-inl.h"
24 #include "mirror/object-refvisitor-inl.h"
25
26 namespace art {
27 namespace gc {
28
DumpRAMAroundAddress(uintptr_t addr,uintptr_t bytes) const29 std::string Verification::DumpRAMAroundAddress(uintptr_t addr, uintptr_t bytes) const {
30 const uintptr_t dump_start = addr - bytes;
31 const uintptr_t dump_end = addr + bytes;
32 std::ostringstream oss;
33 if (dump_start < dump_end &&
34 IsAddressInHeapSpace(reinterpret_cast<const void*>(dump_start)) &&
35 IsAddressInHeapSpace(reinterpret_cast<const void*>(dump_end - 1))) {
36 oss << " adjacent_ram=";
37 for (uintptr_t p = dump_start; p < dump_end; ++p) {
38 if (p == addr) {
39 // Marker of where the address is.
40 oss << "|";
41 }
42 uint8_t* ptr = reinterpret_cast<uint8_t*>(p);
43 oss << std::hex << std::setfill('0') << std::setw(2) << static_cast<uintptr_t>(*ptr);
44 }
45 } else {
46 oss << " <invalid address>";
47 }
48 return oss.str();
49 }
50
DumpObjectInfo(const void * addr,const char * tag) const51 std::string Verification::DumpObjectInfo(const void* addr, const char* tag) const {
52 std::ostringstream oss;
53 oss << tag << "=" << addr;
54 if (IsValidHeapObjectAddress(addr)) {
55 mirror::Object* obj = reinterpret_cast<mirror::Object*>(const_cast<void*>(addr));
56 mirror::Class* klass = obj->GetClass<kVerifyNone, kWithoutReadBarrier>();
57 oss << " klass=" << klass;
58 if (IsValidClass(klass)) {
59 oss << "(" << klass->PrettyClass() << ")";
60 if (klass->IsArrayClass<kVerifyNone, kWithoutReadBarrier>()) {
61 oss << " length=" << obj->AsArray<kVerifyNone, kWithoutReadBarrier>()->GetLength();
62 }
63 } else {
64 oss << " <invalid address>";
65 }
66 space::Space* const space = heap_->FindSpaceFromAddress(addr);
67 if (space != nullptr) {
68 oss << " space=" << *space;
69 }
70 accounting::CardTable* card_table = heap_->GetCardTable();
71 if (card_table->AddrIsInCardTable(addr)) {
72 oss << " card=" << static_cast<size_t>(
73 card_table->GetCard(reinterpret_cast<const mirror::Object*>(addr)));
74 }
75 // Dump adjacent RAM.
76 oss << DumpRAMAroundAddress(reinterpret_cast<uintptr_t>(addr), 4 * kObjectAlignment);
77 } else {
78 oss << " <invalid address>";
79 }
80 return oss.str();
81 }
82
LogHeapCorruption(ObjPtr<mirror::Object> holder,MemberOffset offset,mirror::Object * ref,bool fatal) const83 void Verification::LogHeapCorruption(ObjPtr<mirror::Object> holder,
84 MemberOffset offset,
85 mirror::Object* ref,
86 bool fatal) const {
87 // Lowest priority logging first:
88 PrintFileToLog("/proc/self/maps", LogSeverity::FATAL_WITHOUT_ABORT);
89 MemMap::DumpMaps(LOG_STREAM(FATAL_WITHOUT_ABORT), true);
90 // Buffer the output in the string stream since it is more important than the stack traces
91 // and we want it to have log priority. The stack traces are printed from Runtime::Abort
92 // which is called from LOG(FATAL) but before the abort message.
93 std::ostringstream oss;
94 oss << "GC tried to mark invalid reference " << ref << std::endl;
95 oss << DumpObjectInfo(ref, "ref") << "\n";
96 oss << DumpObjectInfo(holder.Ptr(), "holder");
97 if (holder != nullptr) {
98 mirror::Class* holder_klass = holder->GetClass<kVerifyNone, kWithoutReadBarrier>();
99 if (IsValidClass(holder_klass)) {
100 oss << " field_offset=" << offset.Uint32Value();
101 ArtField* field = holder->FindFieldByOffset(offset);
102 if (field != nullptr) {
103 oss << " name=" << field->GetName();
104 }
105 }
106 mirror::HeapReference<mirror::Object>* addr = holder->GetFieldObjectReferenceAddr(offset);
107 oss << " reference addr"
108 << DumpRAMAroundAddress(reinterpret_cast<uintptr_t>(addr), 4 * kObjectAlignment);
109 }
110
111 if (fatal) {
112 LOG(FATAL) << oss.str();
113 } else {
114 LOG(FATAL_WITHOUT_ABORT) << oss.str();
115 }
116 }
117
IsAddressInHeapSpace(const void * addr,space::Space ** out_space) const118 bool Verification::IsAddressInHeapSpace(const void* addr, space::Space** out_space) const {
119 space::Space* const space = heap_->FindSpaceFromAddress(addr);
120 if (space != nullptr) {
121 if (out_space != nullptr) {
122 *out_space = space;
123 }
124 return true;
125 }
126 return false;
127 }
128
IsValidHeapObjectAddress(const void * addr,space::Space ** out_space) const129 bool Verification::IsValidHeapObjectAddress(const void* addr, space::Space** out_space) const {
130 return IsAligned<kObjectAlignment>(addr) && IsAddressInHeapSpace(addr, out_space);
131 }
132
IsValidClass(const void * addr) const133 bool Verification::IsValidClass(const void* addr) const {
134 if (!IsValidHeapObjectAddress(addr)) {
135 return false;
136 }
137 mirror::Class* klass = reinterpret_cast<mirror::Class*>(const_cast<void*>(addr));
138 mirror::Class* k1 = klass->GetClass<kVerifyNone, kWithoutReadBarrier>();
139 if (!IsValidHeapObjectAddress(k1)) {
140 return false;
141 }
142 // k should be class class, take the class again to verify.
143 // Note that this check may not be valid for the no image space since the class class might move
144 // around from moving GC.
145 mirror::Class* k2 = k1->GetClass<kVerifyNone, kWithoutReadBarrier>();
146 if (!IsValidHeapObjectAddress(k2)) {
147 return false;
148 }
149 return k1 == k2;
150 }
151
152 using ObjectSet = std::set<mirror::Object*>;
153 using WorkQueue = std::deque<std::pair<mirror::Object*, std::string>>;
154
155 // Use for visiting the GcRoots held live by ArtFields, ArtMethods, and ClassLoaders.
156 class Verification::BFSFindReachable {
157 public:
BFSFindReachable(ObjectSet * visited)158 explicit BFSFindReachable(ObjectSet* visited) : visited_(visited) {}
159
operator ()(mirror::Object * obj,MemberOffset offset,bool is_static ATTRIBUTE_UNUSED) const160 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static ATTRIBUTE_UNUSED) const
161 REQUIRES_SHARED(Locks::mutator_lock_) {
162 ArtField* field = obj->FindFieldByOffset(offset);
163 Visit(obj->GetFieldObject<mirror::Object>(offset),
164 field != nullptr ? field->GetName() : "");
165 }
166
VisitRootIfNonNull(mirror::CompressedReference<mirror::Object> * root) const167 void VisitRootIfNonNull(mirror::CompressedReference<mirror::Object>* root) const
168 REQUIRES_SHARED(Locks::mutator_lock_) {
169 if (!root->IsNull()) {
170 VisitRoot(root);
171 }
172 }
173
VisitRoot(mirror::CompressedReference<mirror::Object> * root) const174 void VisitRoot(mirror::CompressedReference<mirror::Object>* root) const
175 REQUIRES_SHARED(Locks::mutator_lock_) {
176 Visit(root->AsMirrorPtr(), "!nativeRoot");
177 }
178
Visit(mirror::Object * ref,const std::string & field_name) const179 void Visit(mirror::Object* ref, const std::string& field_name) const
180 REQUIRES_SHARED(Locks::mutator_lock_) {
181 if (ref != nullptr && visited_->insert(ref).second) {
182 new_visited_.emplace_back(ref, field_name);
183 }
184 }
185
NewlyVisited() const186 const WorkQueue& NewlyVisited() const {
187 return new_visited_;
188 }
189
190 private:
191 ObjectSet* visited_;
192 mutable WorkQueue new_visited_;
193 };
194
195 class Verification::CollectRootVisitor : public SingleRootVisitor {
196 public:
CollectRootVisitor(ObjectSet * visited,WorkQueue * work)197 CollectRootVisitor(ObjectSet* visited, WorkQueue* work) : visited_(visited), work_(work) {}
198
VisitRoot(mirror::Object * obj,const RootInfo & info)199 void VisitRoot(mirror::Object* obj, const RootInfo& info)
200 OVERRIDE REQUIRES_SHARED(Locks::mutator_lock_) {
201 if (obj != nullptr && visited_->insert(obj).second) {
202 std::ostringstream oss;
203 oss << info.ToString() << " = " << obj << "(" << obj->PrettyTypeOf() << ")";
204 work_->emplace_back(obj, oss.str());
205 }
206 }
207
208 private:
209 ObjectSet* const visited_;
210 WorkQueue* const work_;
211 };
212
FirstPathFromRootSet(ObjPtr<mirror::Object> target) const213 std::string Verification::FirstPathFromRootSet(ObjPtr<mirror::Object> target) const {
214 Runtime* const runtime = Runtime::Current();
215 std::set<mirror::Object*> visited;
216 std::deque<std::pair<mirror::Object*, std::string>> work;
217 {
218 CollectRootVisitor root_visitor(&visited, &work);
219 runtime->VisitRoots(&root_visitor, kVisitRootFlagAllRoots);
220 }
221 while (!work.empty()) {
222 auto pair = work.front();
223 work.pop_front();
224 if (pair.first == target) {
225 return pair.second;
226 }
227 BFSFindReachable visitor(&visited);
228 pair.first->VisitReferences(visitor, VoidFunctor());
229 for (auto&& pair2 : visitor.NewlyVisited()) {
230 std::ostringstream oss;
231 mirror::Object* obj = pair2.first;
232 oss << pair.second << " -> " << obj << "(" << obj->PrettyTypeOf() << ")." << pair2.second;
233 work.emplace_back(obj, oss.str());
234 }
235 }
236 return "<no path found>";
237 }
238
239 } // namespace gc
240 } // namespace art
241